Current light-emitting diode (LED) façade lighting uses LED strips composed of a series of LED chips along the strip. A typical LED strip of one meter consists of 100 LED chips that are spaced evenly for continuous and homogeneous illumination. One common problem of the LED strip is related to the reliability of the LED chips. Among the 100 LED chips, it is common to see a few that fail before others, thus creating an uneven illumination along the strip. This is an undesirable effect for façade lighting. More seriously, the LED chips cannot be replaced individually, and the whole strip has to be replaced and re-installed. Therefore, maintenance is very costly. Another disadvantage of the LED strip is its limited bending flexibility, and this occasionally limits its deployment where the façade is curved.
While there are known products using an illuminating waveguide, they are only suitable for small-scale lighting applications such as decorative lighting in automotive or electric devices. The existing technologies do not have the scalability and properties that meet the market needs for a unique façade lighting product in the architectural lighting segment. Further, for these products, the luminance is not high and the illumination is only perceivable in a dark room. Such low level luminance is certainly not sufficient for façade lighting.